Temp sensor for 250 computer

[mattmax]

I bought an Acewell 3200 speedo/odo/tach computer unit for my MC250. The company is Electrosport, they make things for moose and a few other companies.

The directions arent very specific and it seems to be up to the buyer to make half of the hardware. It has a threaded metal plug with wires coming out for a coolant temperature sensor, very similar to what cars have, just smaller.

Does anyone know if there is a plug about 3/8" wide somewhere inthe coolingsystem, or if not, where would be an ideal place to install this sensor. I can either use drill and tap some sort of metal or plastic hose connector or pre-existing fitting, I'm just wondering what part of the motor would temp be most critical?